Polythiocarbamate monomers

ABSTRACT

The invention disclosed is directed to new curable liquid polyene-polythiol compounds containing particular polar groups, at least one unsaturated carbon-to-carbon bond disposed at a terminal position on a main or pendant chain of the molecule and at least one terminally disposed thiol group, with the sum of the unsaturated bonds and thiol groups per polyene-polythiol molecule being at least 3. Upon curling in the presence of a free radical generator such as actinic radiation, the polar polyene-polythiol compounds form solid elastomeric and rigid products which are useful in a variety of applications including coatings, adhesives, sealants and molded articles.

This is a divisional of U.S. Ser. No. 504,410, filed Sept. 9, 1974 andnow U.S. Pat. No. 3,966,794 which is a continuation of U.S. Ser. No.259,148, filed June 2, 1972 and now abandoned.

The present invention relates to curable liquid polyene-polythiolcompounds, processes for preparing the compounds, and to methods forforming solid polythioether products using the compounds.

It is well known in the art that cure of internally unsaturated polymerssuch as polybutadiene or polyisoprene may be effected with polythiols,using a free radical generator. However, such polymers have not provedto be entirely satisfactory in that, after curing, the cured polymericproducts are insufficiently stable in air and other oxygen andozone-containing environments. A number of commerical one-packagesystems, e.g. polyurethanes, are curable upon curing initiation byaqueous moisture in the air. Curing reactions for such systemsundesirably vary due to wide variations in the moisture content of theair. Other drawbacks of moisture-curable polyurethanes include poorappearance and limited strength of the cured products. Such defectsapparently result from gas-evolving reactions of --NCO from thepolyurethane with moisture from the air.

It has now been found that numerous defects of heretofore known curablesystems may be effectively overcome by practice of the present inventionwhich provides new curable liquid polyene-polythiol compounds containingparticular polar functional groups. Upon exposure to a free radicalgenerator, the present compounds may be rapidly and controllably curedto insoluble, crosslinked elastomeric or rigid products.

Generally stated, the curable liquid polyene-polythiol compoundsprovided by the present invention may be represented by the followinggeneral formula:

    (HS).sub.p [G] (X).sub.q

Wherein X is ##STR1## ,n being a numeral from 0 to 9; p and q arenumerals of at least one, and preferably at least 2, the sum of p plus qbeing always at least 3 and preferably at least 4; and G is a polyvalentorganic moiety having a valence of at least 3, free of reactivecarbon-to-carbon unsaturation, free of highly water-sensitive members,and necessarily containing at least one and preferably at least 2 polargroups selected from the group consisting of ##STR2## The substituent onthe substituted amide may be selected from the radical X as definedabove and the members of the group from which the radical R is selectedas set forth below. Where ester, thioester, amide and substituted amideare included as necessarily contained group they are included inbranches of the member G with the members --SH and --X being connectedto the branches. Additional polar functionality such as, for example,carboxylic acid (--COOH), ether (--O--), thioether (--S--), nitrile(--C.tbd.N), quaternary amine salt, chloride, bromide, etc., may beincluded.

The member G may include atoms selected from carbon, oxygen, nitrogen,sulfur, hydrogen, silicon, phosphorus, chlorine, bromine, etc.Typically, G consists of atoms selected from carbon, oxygen, nitrogen,sulfur and hydrogen.

In the groups: ##STR3## n is an integer from 0 to 9 and R is a radicalselected from the group consisting of hydrogen, chlorine, fluorine,furyl, thienyl, pyridyl, phenyl, substituted phenyl, benzyl, substitutedbenzyl, alkyl, substituted alky, alkoxy, substituted alkoxy, cycloalkyl,and substituted cycloalkyl. The substituents on the substituted membersare selected from the group consisting of nitro, chloro, fluoro,acetoxy, acetamide, phenyl, benzyl, alkyl, alkoxy and cycloalkyl. Alkyland alkoxy have from 1 to 9 carbon atoms and cycloalkyl has from 3 to 8carbon atoms.

In general, present polyene-polythiol compounds may be prepared usingrelatively mild conditions by reacting certain types of reactive eneintermediates with thiol (--SH) intermediates. Additional reactiveintermediates may also be used. The conditions must be controlled sothat precuring is avoided and so that concentration of SH groups is notsubstantially reduced. As a general preference, a first intermediatewhich contains one or more functional groups selected from isocyanate,anhydride, acid halide, epoxide and the like is reacted with a secondintermediate containing one or more functional groups such as OH, SH andNH. Using appropriate reactants these reactions provide productscontaining polar groups such as urethane, thiourethane, urea, ester,thioester, amide, carboxylic acid, ether, thioether and amine.Additional polar functionality may be present in the intermediates andincorporated into the products.

The ene intermediate can contain any of the desired reactive functionalgroups other than SH and may be, for example, allyl chloride, allylisocyanate, 9-decenyl isocyanate, vinyl isocyanate, dodecenyl succinicanhydride, acryloyl chloride, allyl glycidyl ether, allyl alcohol, allylhydroxyethyl ether, trimethylolpropane monoallyl ether,trimethylolpropane diallyl ether, pentaerythritol allyl ether,pentaerythritol diallyl ether, pentaerythritol triallyl ether, glycerolallyl ether, glycerol diallyl ether, hydroxy ethyl acrylate, hydroxypropyl acrylate, diallylethanolamine, allylamine and diallylamine. Thethiol intermediates may be monothiols or polythiols containing two ormore thiol groups per molecule and may contain OH and/or NH groups.Where SH functional groups are to be reacted in preparing the presentpolyene-polythiols, polythiol intermediates must be used.

Thiol intermediates useful herein include, for example,2-mercaptoethanol; 2,3-dithiolpropanol; esters of polyols with mercaptoacids such as 2- or 3-mercaptopropionic acid and mercaptoacetic acid,including monomercapto and dimercapto esters of diols such as ethyleneglycol, mono- , di- and trimercapto esters of trimethylolethane,trimethylolpropane, and glycerol, and mono-, di-, tri- and tetramercaptoesters of pentaerythritol; and the like.

Additional intermediates which may be reacted with the ene and thiolintermediates, either separately or in combination are reactiveintermediates which have multiple functionality, contain no --SH orreactive ene groups, and can react with two or more of the abovereactants to provide the polar groups set forth above. Useful additionalintermediates include, for example, polyisocyanates containing two ormore --NCO groups such as 3,3'-dimethyl-4,4'-biphenylene-diisocyanate,hexamethylene diisocyanate,3-isocyanato-3,5,5-trimethylcyclohexylisocyanate,4,4'-methylenebis(cyclohexylisocyanate), 4,4'-methylenebis(phenylisocyanate), polymethylene polyphenyl isocyanate, sulfonyl isocyanate,tolylene diisocyanate, and polymeric diisocyanates prepared by cappingpolymeric diols with diisocyanates; pyromellitic dianhydride and linearpolyanhydrides formed by copolymerizing maleic anhydride with vinylcomonomers such as styrene, ethylene, and methyl vinyl ether;polycarboxylic acids and polycarboxylic acid chlorides; phosgene andchloroformates prepared by reacting phosgene with polyols; polyepoxidessuch as diglycidyl ether of bisphenol A, epoxy novolacs, and4-vinylcyclohexene dioxide; monomeric and polymeric polyols; polyamines;and the like.

Another useful class of the present curable polyene-polythiol compoundsmay be made by preparing allyl ethers of polyols, reacting these etherswith thioacids, hydrolyzing the thioesters produced to preparepolythiols or hydroxythiols and combining the hydrolysis products withthe intermediate hydroxy allyl ethers and reactive intermediates havingmultiple functionality (supra). For example, trimethylol propane may bereacted with allyl chloride in the presence of an equivalent amount ofbase to form the mono-, di- and triallyl ethers. These ethers may thenbe reacted with thioacetic acid by exposure to a free radical generatorsuch as actinic radiation to form the corresponding thioacetates.Hydrolysis of the thioacetates gives dihydroxymonothiol,monohydroxydithiol and trithiol ethers. The last mentioned ethers may bemixed with the mono- or diallyl ethers and reacted with a suitablereactive intermediate such as a diisocyanate, etc., to prepare curablepolyene-polythiols.

The polyene-polythiols of the present invention are essentiallyuncrosslinked compounds having --SH and reactive unsaturatedcarbon-to-carbon groups in pendant, terminal, or near-terminal positionon the polyene-polythiol molecules. As used herein the term reactiveunsaturated carbon-to-carbon groups means ene or yne groups which willreact with thiol groups upon exposure to a free radical generator toproduce the thioether linkage ##STR4## as contrasted to the termunreactive carbon-to-carbon unsaturation which means ##STR5## groupsfound in aromatic nucleii (cyclic structures exemplified by benzene,pyridine, anthracene, and the like) which do not under the sameconditions react with thiols to produce thioether linkages.

In defining the position of the thiol and reactive carbon-to-carbonunsaturated groups, the term terminal means that the groups are at anend of the main chain of the molecule, whereas by near-terminal is meantthat the groups are not more than 10 carbon atoms, and typically lessthan 8 carbon atoms, from an end of the main chain of the molecule. Theterm pendant means that the thiol and carbon-to-carbon unsaturatedgroups are located terminal or near-terminal in a branch of the mainchain in contrast to a position at or near an end of the main chain. Forpurposes of brevity all these positions are referred to herein generallyas terminal, while the reactive unsaturated carbon-to-carbon groups arereferred to as enes, ene groups, etc.

In a class of the present polyene-polythiol compounds, the member [G]contains thiourethane derivatives. A general method provided by thepresent invention for preparing one type of thiourethane-containingpolyene-polythiol is to react an ene-isocyanate with a polythiol whichis free of reactive unsaturated carbon-to-carbon groups, preferably inthe presence of a free radical inhibitor (such as an antioxidant) toessentially prevent premature polythioether-forming reaction of thiolgroups with ene groups. The preparation reaction may be represented bygeneral equation I, which follows: ##STR6## wherein R₁ is a polyvalentorganic moiety free of reactive unsaturated carbon-to-carbon groups andfree of highly water-sensitive members; R₂ is an alkenyl or alkynylgroup containing f terminally positioned ene groups where f is a numeralof at least 1; c is a numeral of at least 3; and b is a numeral chosensuch that c minus b (c-b) is at least 1. The product of b times f (b ×f) be at least 1 and preferably is equal to the difference c-b. Thus, ifc is 3 and f is 1, b and b × f must each be from 1 to 2, and c-b istherefore from 1 to 2; preferably b × f and c-b are each 1.5. If c is 3and f is 2, b can be from 0.5 to 2 and b × f can be from 1 to 4;preferably b is 1 and b × f and c-b are each 2. The reaction is carriedout in an inert moisture-free atmosphere (e.g., nitrogen blanket) atatmospheric pressure at a temperature in the range from 0° to about 120°C. for a period of from about 5 minutes to about 25 hours, preferably inthe presence of the inhibitor supra.

Another embodiment method for preparing thiourethane-containingpolyene-polythiol compounds of the present invention is to react apolythiol, an ene-isocyanate, and a polyisocyanate in the presence of aninhibitor which essentially prevents premature polythioether-formingreaction of thiol groups with ene groups.

In cases where the polythiol is a trithiol, the ene-isocyanate is amonoene and the polyisocyanate is a diisocyanate, the reaction may beillustrated by equation II which follows: ##STR7## wherein R₃ and R₅ arepolyvalent organic moieties free of reactive unsaturated carbon-to-crbongroups and free of highly water-sensitive members; and R₄ is an alkenylgroup wherein the ene group is in terminal position. The reaction iscarried out in an inert moisture-free atomsphere (e.g., nitrogenblanket) at atmospheric pressure at a temperature in the range from 0°to about 120° C. for a period of from about 5 minutes to about 25 hours,as well as in the presence of the inhibitor supra.

Another class of polyene-polythiol compounds provided by the presentinvention contain urethane groups in the backbone of the molecule. Ageneral method of forming one type of polyene-polythiol containingurethane groups is to react the following: an ene-ol of the generalformula R₆ (OH), a thiol-ol of the general formula R₇ (SH)_(x) (OH), anda polyol of the general formula R₈ (OH)_(y), with a polyisocyanate ofthe general formula R₉ (NCO)_(z) wherein R₆ is an organic moietycontaining one or more reactive unsaturated carbon-to-carbon groups; R₇,R₈ and R₉ are polyvalent organic moieties free of highly water-sensitivemembers and free of reactive carbon-to-carbon unsaturation; x is anumeral of at least one; and y and z are numerals of at least 2.Typically, the total number of hydroxyl groups in the ene-ol, thiol-ol,and the polyol is approximately equal to the total number of isocyanategroups in the polyisocyanate. In cases where R₆ (OH) is amonoene-mono-ol, x is 1, y is 6 and z is 2, the overall reaction may beillustrated by equation III which follows: ##STR8##

In carrying out the overall reaction illustrated by equation III above,care must be taken to minimize crosslinking the polyol (R₈ (OH)_(y))with the polyisocyanate (R₉ --NCO)_(z)) to form an insoluble gel. It isfound that formation of insoluble gel may be effectively minimized andtypically may be entirely prevented, by carrying out the reaction in asuitable solvent, e.g., benzene, with or without a catalyst.Conveniently, substantially gel-free urethane-containingpolyene-polythiols may be prepared by way of adding appropriate amountsof the various reactants to a suitable solvent using almost any order ofaddition. The ratio of the total weight of reactants to the weight ofsolvent may have any value which is effective for minimizing gelformation. Addition of about 20 percent by weight reactants to benzeneis suitable.

Generally, it is found that attempted syntheses of the presenturethane-containing polyene-polythiols, theoretically proceedingaccording to reactions illustrated by equation III above, wherein thepolyisocyanate (R₉ --NCO)_(z)) is added to a mixture of the ene-ol (R₆--OH)), thiol-ol (R₇ (SH)_(x) OH), and polyol (R₈ --(OH)_(y)) result inundesirable amounts of insoluble gel formation. In general, suchattempted syntheses in the presence of catalytically effective amountsof catalyst result in entirely unacceptable formation of such gel.

However, it is not necessary that the reaction media include a solventin order to minimize insoluble gle formation when preparing the presenturethane-containing polyene-polythiols. A variety of methods notrequiring solvent may be used. For simplicity, these methods arereferred to herein as solventless methods. However, it is to beunderstood that such methods may be carried out using a suitablesolvent. These solventless methods are especially useful for preparingurethane-polyene-polythiols where the polyisocyanate is an aromaticpolyisocyanate having 2 --NCO groups attached to one benzene ring, e.g.,tolylene diisocyanate. One such solventless method is illustrated by thedescription which follows. The illustration is given for the case oftolyene diisocyanate, the two --NCO groups of which react at differentrates, which difference is especially apparent in the absence ofcatalyst. However, the method illustrated is applicable to almost anypolyisocyanate for which one of its --NCO groups reacts preferentiallyrelative to its other --NCO groups. This method includes reacting theene-ol (R₆ (OH)) with tolylene diisocyanate in a first zone in theabsence of catalyst using a mole ratio of about 1:1 to formpredominantly an ene-isocyanate monoadduct having the general formula##STR9## where R₁₀ is tolylene (CH₃ C₆ H₃ = ). The thiol-ol (R₇ (SH)_(x)OH) is reacted with tolylene diisocyanate in a second catalyst-free zoneusing a mole ratio of about 1:1 to form predominantly a thiol-isocyanatemonoadduct having the general formula ##STR10## The ene-isocyanateadduct is stable in the absence of moisture, etc., and can be storedindefinitely prior to being reacted with the polyol (R₈ --OH)_(y)). Thethiol-isocyanate adduct has limited storage stability in that it reactsto form high molecular weight polythiourea. However, the latter reactionis slower than the reaction of the thiol-isocyanate adduct with thepolyol (R₈ --OH)_(y)). It is found that the desired urethane-containingpolythiol-polyene is formed by reacting appropriate amounts of theene-isocyanate adduct, the thiol-isocyanate adduct and the polyol soonafter the thiol-isocyanate adduct is formed.

Another solventless method includes reacting the polyol (R₈ --OH)_(y))with y moles of tolylene diisocyanate (R₁₀ (NCO)₂) per mole of thepolyol in the absence of catalyst to form a polyisocyanate having thegeneral formula ##STR11## .. This polyisocyanate is then reacted withthe desired amounts of ene-ol (R₆ (OH)) and thiol-ol (R₇ (SH)_(x) (OH))to form the desired polyene-polythiol. Catalyst can be added toaccelerate the second stage of the reaction of tolylene diisocyanate ineither of the above cases. Some care must be exercised since thereaction of isocyanate with thiol will be accelerated as well and toomuch thiol may be used up.

The various reactions used in forming the present urethane-containingpolyene-polythiols are carried out in an inert moisture-free atmosphere(e.g., nitrogen blanket) at atmospheric pressure at a temperature in therange from 0° to about 120° C. for a period of from about 5 minutes toabout 25 hours, as well as in the presence of the inhibitor supra.

Polyene-polythiols containing urea groups may be prepared insubstantially the same general manner as given in the precedingdescription of preparation of urethane containing polyene-polythiolcompounds by substituting polyamine for polyol and polyene-amine forpolyene-ol.

The polyene-polythiols can contain any desirable combination ofurethane, thiourethane and urea groups.

In forming the thiourethane and urethane containing polyene-polythiolsof the present invention, catalytic amounts of a catalyst may beemployed to increase the rate of reaction. Catalysts are especiallyuseful in forming the urethane-containing compounds where an ene-ol isemployed as a reactive intermediate. Suitable catalysts are well knownin the art and include organometallic compounds such as stannousoctoate, stannous oleate, dibutyl tin dilaurate, cobalt acetylacetonate,ferric acetylacetonate, lead naphthanate and dibutyl tin diacetate andtertiary amines such as triethylene diamine. Catalysts are not requiredfor reactions of isocyanate with amines.

Another class of the present polyene-polythiol compounds contains ester,thioester or amide groups in the backbone of the molecule. A generalmethod of forming these products is to react a polyanhydride of thegeneral formula ##STR12## with a polyene-ol of general formula R₁₂ --OH)and a polythiol of general formula R₁₃ (SH)_(e), where R₁₁ and R₁₃ arepolyvalent organic moieties free of reactive unsaturatedcarbon-to-carbon groups and free of highly water-sensitive members, R₁₂is an organic moiety containing at least one and preferably at least 2terminal reactive unsaturated carbon-to-carbon groups, d is a numeral ofat least 2, and e is a numeral of at least one and preferably at least2. Suitable polyanhydrides include pyromellitic dianhydride and linearpolyanhydrides formed by copolymerizing maleic anhydride with vinylcomonomers, e.g., styrene, ethylene, and methyl vinyl ether. Thereaction is illustrated for a dianhydride, diene-ol and trithiol inequation IV below: (IV) ##STR13##

Substitution of an aminodiene for the dieneol gives a polyene-polythiol,a product containing amide groups. This product may be illustrated bythe following general formula wherein R₁₁, R₁₂, and R₁₃ are as definedabove: ##STR14## The two R₁₂ groups may be the same or different.

The reaction is carried out in an inert moisture-free atmosphere (e.g.,nitrogen blanket) at atmospheric pressure at a temperature in the rangefrom 0° to about 120° C. for a period of from about 5 minutes to about25 hours, and in the presence of the inhibitor supra.

Another general method of forming ester, thioester and amide containingpolyene-polythiols is to react polyacyl halides with hydroxy, thiol andamino substituted reactants. A base may be required to take up thehydrogen halide produced as a side product.

The present polyene-polythiol compounds may be cured to solid resins orelastomers either alone or in combination with compatible materials. Forexample, liquid photocurable compositions characterized with rapidcuring rates may be prepared by blending the present polyene-polythiolswith almost any chemical photocuring rate accelerator.

Specifically useful herein are chemical photocuring rate acceleratorssuch as benzophenone, acetophenone, azobenzone, acenapthene-quinone,o-methoxy benzophenone, Thioxanthen-9-one, xanthen-9-one, 7-H-Benz [de]anthracen-7-one, dibenzosuberone, 1-naphththaldehyde, 4,4'-bis(dimethylamino) benzophenone, fluorene-9-one, 1'-acetonaphthone,2'-acetonaphthone, anthraquinone, 1-indanone, 2-tert.-butylanthraquinone, valerophenone, hexanophenone, 8-phenyl-butyrophenone,p-morpholinopropiophenone, 4-morpholino-benzophenone,4'-morpholinodeoxybenzoin, p-diacetylbenzene, 4-aminobenzophenone,4'-methoxyacetophenone, benzaldehyde, α-tetralone, 9-acetylphenanthrene,2-acetylphenanthrene, 10-thioxanthenone, 3acetylphenanthrene,3-acetylindole, 1,3,5-triacetylbenzene and the like, including blendsthereof, to greatly reduce the exposure times.

The curing rate accelerators are usually added in an amount ranging fromabout 0.0005 to about 50 parts by weight, and preferably from about 0.05to about 25 parts by weight, per 100 parts by weight of thepolyenepolythiols. Preferred photocuring rate accelerators are thealdehyde and ketone carbonyl compounds having at least one aromaticnucleus attached directly to the ##STR15## group.

The present curable compounds and curable compositions formulatedtherewith are characterized by insensitivity to visible light, renderingthem generally free from setting on, for example, apparatus which may beused to apply the composition to a substrate. Upon exposure to actiniclight, the present curable compositions are found to be rapidly curable,making them eminently suitable for use in high speed coating operations.

A class of actinic light useful herein for curing is ultraviolet lightand other forms of actinic radiation which are normally found inradiation emitted from the sun or from artificial sources such as typeRS sunlamps, carbon arc lamps, xenon arc lamps, mercury vapor lamps,tungsten halide lamps and the like. Ultraviolet radiation may be usedmost efficiently if the curable polyene/polythiol compound contains asuitable photocuring rate accelerator.

Curing periods may be adjusted to be very short and hence commerciallyeconomical by proper choice of ultraviolet source, photocuring rateaccelerator and concentration thereof, temperature and molecular weight,and number of ene and thiol groups per molecule of thepolyene-polythiol. Curing periods of less than about 1 second durationare possible in some applications.

Conventional curing inhibitors or retarders which may be used in orderto stabilize the components of the curable compositions so as to preventpremature onset of curing may include hydroquinone; p-tert.-butylcatechol; 2,6-ditert.-butyl-p-methylphenol; phenothiazine;N-phenyl-2-naphthylamine; inert gas atmospheres such as helium, argon,nitrogen and carbon dioxide; vacuum; and the like.

Blends and mixtures of the polyene-polythiols are also operable hereinfor forming crosslinked polythioether end products.

The compositions to be cured, i.e., (converted to solid resins orelastomers) in accord with the present invention may, if desired,include such additives as antioxidants, accelerators, dyes, inhibitors,activators, fillers, pigments, anti-static agents, flame-retardantagents, thickeners, thixotropic agents, surface-active agents, viscositymodifiers, extending oils, plasticizers, tackifiers and the like withinthe scope of this invention. Such additives may be blended with thepolyene-polythiol using conventional blending techniques.

Operable fillers include natural and synthetic resins, carbon black,glass fibers, wood flour, clay, silica, alumina, carbonates, oxides,hydroxides, silicates, glass flakes, glass beads, borates, phosphates,diatomaceous earth, talc, kaolin, barium sulfate, calcium sulfate,calcium carbonate, antimony oxide and the like. The aforesaid additivesmay be present in quantities up to 500 parts or more per 100 partspolyene-polythiol by weight and preferably about 0.0005 to about 300parts on the same basis.

Liquid curable compositions comprising the present polyene-polythiolcompounds are readily cured to the solid state by exposing to a freeradical generator such as actinic radiation (preferably UV light); highenergy radiation such as electron beams; and chemical initiators such asorganic peroxides, diazo compounds and the like. Useful end productswhich may be formed are numerous and varied and include, for example,adhesives, coatings, sealants and molded articles such as gaskets,tires, etc.

The present invention will be further illustrated by the followingnon-limiting examples. Throughout this disclosure all parts andpercentages given are by weight unless otherwise indicated.

EXAMPLE 1

448 Grams (1 mole) of pentaerythritol tetrakis (2-mercaptopropionate),166 grams (2 moles) of allyl isocyanate, 0.65 grams of dibutyl tindilaurate, and 0.65 grams of Ionol (trademark for a phenol producthaving anti-oxidant properties by the Shell Chemical Corp.) were heatedwith stirring under nitrogen in a vessel at 70° C. for about 30 minutesto 1 hour. The product was cooled and discharged from the vessel.Analysis of the product showed it to be a diene-dithioldithiourethanehaving a thiol-ene functionality of 4, a molecular weight of 614, andthe following average formula: ##STR16##

6.5 Grams of benzophenone and 0.65 gram of hydroquinone were added tothe product at room temperature and mixed in a vessel. The resultingliquid mixture was poured at room temperature onto a substrate coatedwith a silicone release agent. The layer was leveled to a substantiallyuniform thickness of about 60 mils and thereafter exposed to a type RSsunlamp at an intensity of about 4000 microwatts per square centimeteron the exposed surface. Observations showed that the film was cured onits exposed surface to a thin film after about 10 seconds and was curedclear through in about 40 seconds. The cured slab was peeled from thesubstrate and subjected to physical property tests which showed atensile modulus of about 1160 pounds per square inch, a tensile strengthof about 390 pounds per square inch, and 50% elongation at failure.

EXAMPLE 2

800 Grams (2 moles) of trimethylol propane tris(betamercaptoproprionate), 174 grams (1 mole) tolylene diisocyanate, 166grams (2 moles) allyl isocyanate, 0.5 gram dibutyl tin dilaurate and 0.5gram Ionol were mixed in a vessel and heated to 70° C. for 1 hour whilepassing nitrogen through the vapor space of the vessel. After adding 5grams benzophenone and 0.5 gram hydroquinone to the liquid reactionmass, the product was cooled and discharged from the vessel. Analysis ofthe product showed that it consisted principally of an 1140 molecularweight tetrathiourethane-diene-dithiol having the following formula:##STR17## The thus prepared composition was poured onto a flat Mylarsupport and leveled to a uniform 10-mil thickness using a doctor blade.Thereafter the layered composition was exposed to a type RS sunlamp of250 watts power positioned about 6 inches above the composition forabout 15 minutes, during which time the liquid composition cured or setto a tough, flexible solidified resin. Tests showed that the resinarticle has a Shore D hardness of 16.

EXAMPLE 3

To 9000 grams of benzene in a reaction flask was added 700 grams (1mole) of a commercially available hexol adduct of Inositol and propyleneoxide, sold under the tradename NIAX Polyol LS-490 by Union CarbideCorp., 232 grams (4 moles) of allyl alcohol, 248 grams (2 moles) of2,3-dimercaptopropanol, 0.5 gram dibutyl tin dilaurate and gradually,with good stirring, 1044 grams (6 moles) tolylene diisocyanate. Themixture was maintained at 65° C. by the heat of the reaction andmaintained thereat for about 1 hour after the addition of thediisocyanate. Benzene was stripped from the 20 weight percent solutionof the reaction product using an applied vacuum of about 2 mm. ofmercury while heating the reaction mixture to about 100° C. The hexoladded had the following formula: ##STR18## wherein n is a numeral from 1to 2, with n being, on the average, about 1.5 per molecule. The strippedresin product consisted principally of atetrathiol-tetraenedodecaurethane having the following formula:##STR19## wherein n is as defined above. The product having an averagemolecular weight of 2224 was a solid at room temperature but a liquid at70° C.

A liquid photocurable composition was prepared by heating 112 grams ofthe product to 70° C. and mixing it with 1.8 grams of benzophenone and0.2 gram of 2,6-di-t-butylmethylphenol. The liquid curable compositionwas poured onto a Mylar (terephthalate ester product by DuPont) film ofabout 3 mils thickness and leveled to a liquid depth of about 25 milsusing a doctor blade. Thereafter the applied composition was exposedthrough a photographic negative adhered to a glass plate positionedabout 5 mils above the curable layer to a xenon arc lamp at a liquidsurface intensity of about 4000 microwatts per square centimeter forabout 10-15 minutes, during which time the liquid composition was foundto cure substantially through its thickness in the exposed areas. Thecurable composition in the unexposed areas remained a liquid ofessentially the same viscosity as that of the composition prior toexposure and was removed by immersion for about 3 minutes in an agitatedaqueous bath containing 10% of a detergent commercially available underthe trade mark "LIQUI-NOX" from Alconox Inc. Next, the printing platebeing formed was removed from the bath and dried in air at about 80° C.Printing ink was applied to the relief image areas using an inkingroller in conventional manner, and the inked plate was pressed againstnewsprint paper for a short period of time resulting in transferring inkin the image areas to the paper. Excellent image definition and fidelitywere observed on the printed paper.

EXAMPLE 4

700 Grams (1 mole) of NIAX Polyol LS-490 (the hexol of Example 3), 232grams (4 moles) of allyl alcohol, 248 grams (2 moles) of2,3-dimercaptopropanol, and 0.65 grams of dibutyl tin dilaurate wereheated to 70° C. in a nitrogen-blanketed glass reaction flask. 1044grams (6 moles) of tolylene diisocyanate was slowly added to the heatedbulk reaction mixture with stirring. Prior to completing the tolylenediisocyanate addition, a solid crosslinked insoluble mass resulted inthe vessel. The mass was useless as a curable composition forcontrollably forming solid polythioether sealants, coatings, moldedarticles, etc.

EXAMPLE 5

696 Grams (4 moles) of tolylene diisocyanate was added to 232 grams (4moles) of allyl alcohol in a stirred reaction flask under a nitrogenblanket. These reactants were heated to 70° C. and maintained thereatwith stirring for about 3 hours. The principal component of the reactionproduct was a urethane-containing monoadduct having the formula:##STR20## The product of this reaction will hereinafter be referred toas Product A. 348 grams (2 moles) of tolylene diisocyanate was chargedto a second stirred reaction flask containing 248 grams (2 moles) of2,3-dimercaptopropanol. These reactants were heated to 80° C. andmaintained thereat with stirring for about 3 hours. The thus formedproduct included as its principal component the dithiolurethane-containing monoadduct having the formula: ##STR21## Thisproduct will be referred to hereinafter as Product B.

0.5 gram of Ionol (a commercially available phenol anti-oxidant), halfof Product A, and half of Product B were mixed in a stirred vessel andthe mixture was added to a reaction flask containing a mixture of 0.25gram of dibutyl tin dilaurate with 350 grams (0.5 mole) of Niax PolyolLS-490 (the hexol of Example 3). This reaction flask was heated to 70°C. under a nitrogen blanket and the reaction was continued with stirringat 70° C. for 1 hour. The principal component of the resulting productwas found to be a tetrathiol-tetraene dodecaurethane having the formulagiven in Example 3 for the tetrathiol-tetraene product thereof.

The remaining half of Product A was added to a stirred reaction flaskcontaining 0.25 gram of stannous octoate, 0.5 gram of Ionol, and 350grams (0.5 mole) of Niax Polyol LS-490. The thus formed reaction mixturewas heated to 70° C. and the reaction was continued thereat for 1 hour.Next, the remaining half of Produt B was charged to the reaction mixtureand the temperature was maintained at 70° C. with stirring for 1 hour.The reaction product using this sequence was substantially the same asthat obtained using the above procedure wherein Product A and Product Bwere simultaneously added to the hexol.

EXAMPLE 6

348 Grams (2 moles) of tolylene diioscyanate and 116 grams (2 moles) ofallyl alcohol were heated with stirring in a vessel under a nitrogenblanket at a temperature of about 65° C. for about 1 hour. Thereafter,0.5 gram of Ionol, 448 grams (1 mole) of pentaerythritol tetrakis (2-mercaptopropionate) and 0.5 gram of stannous octoate were added and thereaction was continued for about 1 hour at 100° C. 0.5 gram ofhydroquinone and 5 grams of acetophenone were added with stirring to themixture, which thereafter was cooled and discharged from the vessel. Theprincipal component of the product was a 912 molecular weightdiurethane-dithiourethane-dienedithiol having the following formula:##STR22##

A printing plate was formed form this photocurable composition using theprocedure of Example 3. The results were substantially the same.

EXAMPLE 7

214 Grams (1 mole) of trimethylol propane diallyl ether and 167 grams(2.2 moles) of thioacetic acid were added to a Pyrex tube, 10 inches inlength and 2 inches in diameter. A low pressure mercury lamp enclosed ina 1-inch diameter quartz tube was then immersed in the mixture, andirradiation was carried out using the lamp for 20 hours with stirring.Excess thioacetic acid was removed from the resulting yellow viscousliquid in a rotary evaporator. The residue was heated to 140° C. at 0.5mm. of Hg to remove any volatile material that might be present. Aftercooling, the yellow liquid was decolorized using conventional charcoalabsorption techniques. The liquid addition product was placed in a1-liter, three-neck, round bottom flask equipped with mechanical stirrerand reflux condenser. An aqueous solution of 60 g. sodium hydroxide in180 ml. H₂ O was added, and the resulting mixture was heated withstirring for 5 hours. After cooling to room temperature, the reactionmixture was extracted with 500 ml. of diethyl ether and the ether layerseparated. Ether was removed by distillation and the liquid residue washeated to 125° C. at 0.5 mm. of Hg for 1 hour to remove any volatilematerials that might be present. The resulting colorless liquid residuewas found to consist essentially of trimethylolpropane di(3-mercaptopropyl) ether and was cooled to 25° C. for subsequent use.

To a 3-liter reaction flask containing 1 gram Irganox 1076 (an oxidationstabilizer commercially available from Geigy Chemical Co. and believedto be a dodecyl ester of 4-hydroxy-3,5-di-t-butyl phenyl propionicacid), in 214 grams (1 mole) trimethylol propane diallyl ether under anitrogen blanket was added, with stirring, 174 grams (1 mole) tolylenediisocyanate. Next, the reaction mixture was heated to 70° C. andmaintained thereat with continued stirring for 30 minutes. The principalcomponent of the resulting product was found to be a diene having thefollowing formula: ##STR23## After cooling this diene-containing mixtureto about 25° C., 278 grams (1 mole) of the previously formed trimethyloldimercaptopropyl ether was added, which addition was followed by adding0.33 gram dibutyltin dilaurate. The reaction mixture was warmedgradually to 70° C. with stirring, and the reaction was continued untilthe --NCO content was reduced to essentially zero. The thus formedliquid reaction product was found to consist essentially of adiurethane-dithiol-diene having the following formula: ##STR24## 5 gramsbenzophenone (UV sensitizer) was stirred into the preceding liquiddithiol-diene product. The resulting sensitized mixture was poured ontoaluminum sheet, spread into a 20-mil layer, and thereafter exposed to atype RS sunlamp for 2-3 minutes, during which time the liquidcomposition cured to a solid, odorless, elastomeric coating.

EXAMPLE 8

98 Grams (1 mole) of diallylamine was added to a stirred 3-liter flaskcontaining a solution of 1 gram of Irganox 1076 and 612 grams ofstyrene/maleic anhydride copolymer in 1110 grams of benzene undernitrogen. The copolymer had molecular weight of about 1700 and included2 polymerized styrene units per polymerized anhydride unit. Afterrefluxing the reaction mixture for 1 hour at 80°-82° C., 399 grams oftrimethylolpropane tris (β-mercaptopropionate) was added quickly andreaction was continued with refluxing at 80°-82° C. for 1 hour. Theprincipal component of the product consisted essentially of repeatedunits having the formula: ##STR25##

10 Grams of benzophenone per 100 grams of polymer was added withstirring to the benzene solution of this polymeric diene-dithiolproduct, and thereafter a piece of paper was dipped into the solution.After withdrawing the solution coated paper, benzene was removed undervacuum at 70° C. The remaining paper-disposed polymer composition wasexposed to a type RS sunlamp until a firm, tough polythioether-papercomposite was formed.

EXAMPLE 9

A reaction mixture was formed by adding to a steam-jacketed stainlesssteel reaction kettle, 103 grams (1 mole) of diethylenetriamine, 285grams (2.5 moles) of allyl glycidyl ether, 150 grams (2.5 moles) ofethylene sulfide and 0.5 gram Ionol (to prevent premature --SH additionto the carbon-to-carbon double bond). A nitrogen blanket was provided onthe kettle and a steel cover was secured thereon so as to seal thekettle. Steam was introduced into the jacket resulting in increasing thetemperature of the reaction mixture to 95° to 100° C. and increasing thekettle pressure to about 35 pounds per square inch gauge (psig).Reaction was continued with heating and stirring until the reactionpressure was decreased to less than 5 psig. Thereafter the reactor wasvented to atmospheric pressure and excess volatile material was carriedoff using nitrogen as the carrier. The thus formed liquidpolyene-polythiol product included an average of 2.5 equivalens per moleof product of --NCH₂ CH₂ SH) and 2.5 equivalents per mole of product of##STR26## After dissolving 1 gram benzophenone (UV sensitizer) in theproduct, the sensitized liquid composition was spread into a thin film,and cured under a sunlamp to a solid elastomeric polythioether polymer.

The present polyene-polythiol compounds, upon exposure to a free-radicalgenerator, e.g., actinic radiation and preferably ultraviolet light,form cured polythioether products having many and varied uses. Examplesof some uses include but are not limited to adhesives; caulks;elastomeric sealants; coatings; encapsulating or potting compounds;liquid castable elastomers; thermoset resins; impregnants for fabric,cloth, fibrous webs and other porous substrates; laminating adhesivesand coatings; mastics; glazing compounds; fiberglass reinforcedcomposites; sizing or surface finishing agents, filleting compounds;cure in place gasketing compounds; rocket fuel binders; foamablethermosetting resins or elastomers; molded articles such as gaskets,diaphragms, balloons, automobile tires, photoresists, photocurableprinting plates, etc. The increased polarity of the presentpolyene-polythiols aids in forming cured polythioethers having greatlyimproved performance characteristics such as higher tensile strength,greater elongation, improved adhesiveness to substrates, and the like.

As used herein highly water-sensitive groups are intended to include,for example, isocyanate, acylhalide such as acylchloride, anhydride andthe like which readily react with water, alcohols, amines, ammonia andthe like.

It is to be understood that the foregoing detailed description is givenmerely by way of illustration and that numerous modifications may bemade therein without departing from the spirit or scope of the presentinvention.

What is claimed is:
 1. A compound having the formula ##STR27##
 2. Acompound having the formula ##STR28##